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From: Tycho Andersen on 8 May 2010 17:00
On Sat, May 8, 2010 at 3:41 PM, Oltmans <rolf.oltmans(a)gmail.com> wrote:
> Hi, I've a list that looks like following
>
> a = [ [1,2,3,4], [5,6,7,8] ]
>
> Currently, I'm iterating through it like
>
> for i in [k for k in a]:
>        for a in i:
>                print a
>
> but I was wondering if there is a shorter, more elegant way to do it?

How about itertools? In python 2.6:

>>> a = [ [1,2,3,4], [5,6,7,8] ]
>>> from itertools import chain
>>> for i in chain(*a):
.... print i
....
1
2
3
4
5
6
7
8
From: Oltmans on 8 May 2010 17:06
On May 9, 1:53 am, superpollo <ute...(a)esempio.net> wrote:

> add = lambda a,b: a+b
> for i in reduce(add,a):
>      print i

This is very neat. Thank you. Sounds like magic to me. Can you please
explain how does that work? Many thanks again.

From: Günther Dietrich on 8 May 2010 17:09
Tycho Andersen <tycho(a)tycho.ws> wrote:

>On Sat, May 8, 2010 at 3:41 PM, Oltmans <rolf.oltmans(a)gmail.com> wrote:
>> Hi, I've a list that looks like following
>>
>> a = [ [1,2,3,4], [5,6,7,8] ]
>>
>> Currently, I'm iterating through it like
>>
>> for i in [k for k in a]:
>>        for a in i:
>>                print a
>>
>> but I was wondering if there is a shorter, more elegant way to do it?
>
>How about itertools? In python 2.6:
>
>>>> a = [ [1,2,3,4], [5,6,7,8] ]
>>>> from itertools import chain
>>>> for i in chain(*a):
>... print i
>...
>1
>2
>3
>4
>5
>6
>7
>8


Why not this way?

>>> a = [[1,2,3,4], [5,6,7,8]]
>>> for i in a:
.... for j in i:
.... print(j)
....
1
2
3
4
5
6
7
8

Too simple?



Best regards,

Günther
From: Tycho Andersen on 8 May 2010 17:40
On Sat, May 8, 2010 at 4:09 PM, Günther Dietrich
<gd.usenet(a)spamfence.net> wrote:
[snip]
> Too simple?

No, not at all. I really only intended to point the OP to itertools,
because it does lots of useful things exactly like this one.

\t
From: Lie Ryan on 9 May 2010 01:17
On 05/09/10 07:09, Günther Dietrich wrote:
>
> Why not this way?
>
>>>> a = [[1,2,3,4], [5,6,7,8]]
>>>> for i in a:
> .... for j in i:
> .... print(j)
> ....
> 1
> 2
> 3
> 4
> 5
> 6
> 7
> 8
>
> Too simple?

IMHO that's more complex due to the nested loop, though I would
personally do it as:

a = [ [1,2,3,4], [5,6,7,8] ]
from itertools import chain
for i in chain.from_iterable(a):
print i

so it won't choke when 'a' is an infinite stream of iterables.
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